Combustion tube heater for cooking containers



Oct. 26, 1948. l R, T, KEA-UNG 2,452,472

GOMBUSTION TUBE HEATER FOR COOKING CONTAINERS Filed Nov. 4, 1944 2 Sheets-Sheet 2 INVENTOR.

Patented Oct. 26, 1948 CQMBUSTIQN TUBE HEATERFOR COOKING CONTAINERS.

Richard T. Keating, Oak Park, Ill. Application November 4, 1944:, Serialy No. 561,851

8v Claims'. (Cl. 126-391) Thisl invention relates to improvements in a combustion tube heater for cooking. containers used for frying doughnuts, potatoes and other products.

It is an object of my invention to provide a deepA fryer so arranged and combined as to Droduce trom a given quantity of heating fuel a maximum of useful working heat capacity.

A further object of my invention is to provide a deep fryer with a heatv distributing Chamber so arrangedv and combined as to eiciently prevent the Waste of heat-producing fuel.

Itis a further object of my invention to provide a deep fryer so arranged as to eciently utilize the heat-producing elements of the fuel before being discharged.

It is. a further object of my invention to provide in av deep fryer a combustionv chamber so arranged and combined with its, fuel snpply as to provide in operation a central longitudinally extending combustion flame extending substan.. tially across the vattraveling in one. direction, surrounded by an envelope of substantially burnt hot gases` traveling in the opposite. direction to minimize the deposition of carbonaceous mate,- rial or soot on the inner Walls of the'combustion chamber.

The above and other advantages and capabilities of my invention Will be apparent from a detailed description of the accompanying drawings in which I have illustrated one form of my invention, but the construction therein shown is to be understood as illustrative and not as denning the limits of my invention. 1

In the accompanying drawings:

Figure 1 is a perspective view of a deep fryer embodying one form of my invention;

Figure 2 is a transverse sectional view taken on theline 2.-..-2 of Figure l;

Figure 3 is a perspective view of my heatfex changer separate and apart from the frying vat;

Figure 4 is a vertical longitudinal sectional view on the line 4-4 of Figurek 1 looking in the direction indicated by the arrow; and

Figure. 5 is a sectional view taken on the line 5 5 of Figure 4, also looking. in the direction indicated by the arrows.

Referring to the drawings in detail, my deep fryer consists of a casing l 0 rectangulary in shape having side and. end members constructedlof. `suitable metal. Formed integrally with the. sides and ends of the casing is a depressed metal frying Vat Il. The bottom of this vat, as shown, is v-shaped in cross section, and provided with a drain discharge valve VIt at `its lowestY point, as

bestl shown in Figure 2; The vat isv provided with inwardly extending ledges I3, I4', I5 and" IS'near the top of the casing So that the vatlthrough a substantial portion of its depth is offset inwardly Vfrom the casing, the greatest offset being at the forward or burner end, leaving a substantial space around the vat, between the outer wallsv of the vat and thewalls of the casing, forming an air chamber therebetween.

Mounted in the vatV intermediate itstopy and bottom is an immersed heater unit Il having af combustion chamber I8` of cylindrical form in cross section having a relatively large diameter, It is positioned directly above the apex ofA the- Vshaped bottom. The intake end of this combustion chamber passes through an opening in the front wall 32 of the Vat andis supported thereby; there being provided a suitableuid tight connection between the intake and hot combustion chamber and the front wall of the vat. The

combustionV chamber extends across the vat toa` point near the rear end wall I8' of the vat and is supported b yy the rearwall I8 by means ofa relatively small tube 20, oneend of which tube- 20 communicates with the interior of the com-.-V bustionk chamber. This tube isv eccentri'eally. mounted in the circular endvwall IS'of the combuse tion chamber, as best. shown in Figure 2. The opposite endl oi?V the tube 2lil passes through ani opening in the rearl end wallv I8 ofthe Vat and discharges into an. elongated chamber 2|., which chamberI is rigidly nxed by any suitable.r means' to and on the outside of the rear wall of the casing I0. The chamber 2| in turn communicates with a` vertical discharge gas flue or stack; 2.2,. which stack is provided with ay control valve ory damper 23.

suitably fixed tothe combustion. chambernear its intake end are two cylindrical. heat exchangers 24 and 25y having.- diameters preferably substan-A tially less than the` diameterof the combustion 24 and 25 pass through Suitable openings in the rear wall of the. vat4 and the, .rear wall ofptha casing.: and discharseinto thechamber .2.1, Suit.-

surface of the combustionv chamber.. The opposite ends oi` the exchangers'.

able liquid tight connections are provided in such openings between the exchangers and the rear Walls of the vat and casing.

Secured to the forward end of the exchanger by any suitable means, as best shown in Figures 4 and 5, is a burner housing 26. In this housing is mounted a suitable fuel burner 21 connected by a suitable conduit 28, or other means, to a4 supply source of fuel. The forward end of the burner housing is provided with openings. Attached to the forward end of the burner housing `by any suitable means is a blower housing 29.

Within this housing is mounted by any suitable means a blower 30 adapted to be driven by a suitable motor 3l or other source of power. The housing 26 connected to the intake end of the combustion chamber is preferably cylindrical in form and of the same diameter as the combustion chamber. i

'I he burner 2l is positioned substantially at the axialrcenter of the housing 26 and near the intake end ofthe combustion chamber so that when the burner is lighted and the blower put in operation a' central core of flame is driven centrally through the combustion chamber toward the end Wall I8, during which travel substantially most of the combustion takes place: Due to the fact that the combustion chamber. at one end is closed except for the relatively small discharge opening 20, mostof the flue gas is caused to travel in the com` bustion chamber in a direction opposite to the travel ofthe flame, surrounding and enveloping thetraveling core of iiame. The burnt gases pass out through the openings communicating with the heat exchangers, whereupon their direction of travel is reversed and they are passed entirely through the immersed heat exchangers and dischargedrinto the chamber 2|, as best shown in Figure 5. This construction, which in operation affords a central core of burning fuel or flame traveling inone direction, a surrounding or enveloping ring of burnt gases traveling in the opposite direction interposed between the Walls of the combustion chamber, and the central core of burning fuel, minimizes thev deposition of carbonaceous material, soot and the like on the vinner walls` of theco'mbustion chamber, avoiding hot spots and greatly extending the life of the ccmbustion chamber andthe troublesome problem of frequent clean-out periods. Further, the combustion chamber provides an excellent heat exchanger due to the fact that the hot gases from the burnt Vfuel are caused'to travel in a reverse direction from the iiame in the form of a movingl duced from'the flame for av given quantity of fuel I is further utilized and transferred tothe contents of the vat for @doing useful work by virtue of the fact that after the burntgases have traveled lengthwise of the combustionchamber in the manner above stated, they pass on into the heat exchangers and Ythence lengthwise throughthese exchangers before being discharged into thel chamber 2|. It will thus vb'eseen that there is a greatly improvedexch'angeof heat from a'given amountfof fuelto the contents lof the vat. n

Inlmy invention the V-sha'ped bottom of the vat serves 4an important purpose in combination with 4my relatively large combustion chamber whichis positioned ,directlyfover the apex of the V- shaped bottom asV this permitsthe ,immersion of the relatively largeA combustion chamber in a minimum supply of fat in the vat. This is important, first, because the fat is expensive, and secondly, a smaller volume of fat is required for any given operation than would be the case if the bottom of the vat were perfectly straight. Further, the arrangement affords an additional advantage in that it provides a relatively deep volume of liquid below the combustion chamber whichin practice would be termed a cold zone immediately below the combustion chamber where crumbs and the like are permitted to collect.

In the vat is a suitable Wire mesh product container which extends well down into the vat and is supported on and by the combustion chamber and heat exchangers in the vat. This basket is so arranged and mounted as to be readily removed and replaced for loading and unloading the doughnuts or other products being fried.

In operation, the vat is supplied With fat or frying iiuid so as to immerse not only the combustion chamber and the heat exchangers, but productsin the wire mesh basket or container. The fuel in the cup 2l from which the heating iiuid is discharged is ignited. The blower 30 is set in operation, which forces the burning flame of the fuel burner centrally through the cylindrical combustion chamber longitudinally in one direction. A back pre"sure is set up in the combustion chamber by virtue of the fact that its end is closed save for a restricted eccentric relatively small dischargeflue. The hot gases produced by the burning flame, asbest shown in Figure 5, travel in a longitudinal direction parallel with but in reverse directionr to the travel of the flame iny thev formv of a ring or envelope surrounding the name and in direct contact with the inner cylindrical wall of the combustion chamber and thence outwardly into the heat exchangers 2li and 25 and thence through the heat exchangers in direct contact with the inner cylindrical walls thereof parallel with and in the same direction of travel as theame, from which exchangers the flue gases are discharged into the chamber 2 I. A relatively small amount of the heated gas is discharged direct from the combustion chamber through the constricted relatively small eccentric discharge 20. y

It will be seen that with my arrangement and combination the heat producing components of ,the fuel are efficiently utilized and put to useful work rather than being wasted and that the heat produced by any given amount of fuel is effectively exchanged or transferred from the combustion chamber and heat exchangers to the stack without imparting all its useful heating energy to the .fat or frying fluid in the vat.

From the foregoing description it will becomel yapparent that I have provided an apparatus which results in a great saving of fuel by preventing waste vof heating energy and effectively utilizing the heat-producing components of anyl given amount of fuel.

Having thus described my invention, claim:A

1. Aydeep fryer comprising in combinationa frying fluid vat, a relatively large cylindrical longitudinally extending combustion chamber mounted irland extending .substantially across said vat and adapted to be immersed in frying fluid when said apparatus is in normal operation, said chamber having a name intake at one end and its opposite end closed save for a relatively constricted outlet, said outlet being eccentrically located with respect to the axis of said chamber, ue gas discharge means near the intake end of the combustion chamber, and a pressureoperated fuel-burning device disposed adjacent the llame .intake for projecting .a central burning core of fuel longitudinally through .said .combuse tion chamber in one direction, said opposite end of said chamber causing a .ring or envelope of burnt; gases surrounding `andin contact with said burning fuel to travel through said combustion chamber in the opposite direction and out said flue gas discharge means near the intake of the combustion chamber to minimize the deposition of carbon or soot in the combustion chamber.

2. A deep fryer comprising in combination a frying fluid vat, `a .relatively large cylindrical longitudinally extending combustion .chamber mounted in and extending substantially across said vat and adapted to be immersed in frying fluid when said apparatus is in normal operation, said chamber having a name intake at one end and its opposite end closed save for a relatively constricted outlet, nue gas discharge means near the intake end of the combustion chamber, a pressure-operated fuel-burning device disposed adjacent the ame intake for projecting a central burning core of fuel longitudinally through said combustion chamber in one direction, said opposite end of said chamber causing a ring or envelope of burnt gases surrounding and in contact with said burning fuel to travel through said combustion chamber in the opposite direction and out said flue gas discharge means near the intake of the combustion chamber to minimize the deposition of carbon or soot in the combustion chamber, and heat exchangers connected with the flue gas discharge means andextending across the vat and having their longitudinal axes spaced from and parallel with the combustion chamber through which the heated gases travel in a direction with the flame in the combustion chamber for efficiently transferring the heat from the combustion chamber and exchangers to the fluid in the vat.

3. In a deep fryer, a vat, a relatively large cylindrical combustion chamber extending across the vat having a name intake at one end with its opposite end closed save for a constricted eccentric relatively small outlet yue, heat exchangers communicating with said combustion chamber near its intake end spaced from and extending parallel to the combustion chamber, a fuelburner disposed adjacent said intake end for developing a flame, a blower for forcing the flame to travel centrally through the combustion chamber in one direction, said substantially closed end forcing the flue gases to travel in a reverse direction substantially through the combustion chamber in the form of a ring or envelope surrounding and in contact with the traveling llame and into the heat exchangers and through the exchangers across the vat in the same direction as the flame in the combustion chamber.

4. In a deep fryer, a vat having a bottom V- shaped in cross section, a relatively large cylindrical longitudinally extending combustion chamber mounted in said vat immediately above the apex of the V-shaped bottom, said combustion chamber having a flame intake at one end, rela1 tively small cylindrical longitudinally extending heat exchangers communicating adjacent the intake and rigidly fixd to the combustion chamber and spaced therefrom with their upper surfaces substantially in a plane with the upper surface of the combustion chamber and so arranged as to form a support for a products container positioned in the vat, a fuel burner near the intake En end of :said combustion chamber, and pressure means for causing the vflame vto travel centrally and longitudinally through said combustion chamber in one direction, said combustion chamber having an integral vmember for substantially closing its end opposite said name intake, said member causing a ring or envelope of flue gas surrounding the dame to travel ythrough said combustion chamber in a reverse direction and through said exchangers in the same direction as the travel'of the flame.

5. The fcombination of a ycombustion chamber tube and `a pair of L-shaped heat-exchanger tubes communicating with the intake end of said combustion chamber tube adjacent the burner end thereof and having their main body portions extending parallel to said combustion chamber tube, a constricted relatively small outlet flue eccentrically mounted in the end of said combustion chamber tube, said combustion chamber tube having its intake end, opposite the burner end, closed, except for said constricted relatively small outlet flue.

6. A tubular combustion chamber having an open fiarne intake end, with its opposite end closed save for a constricted eccentric relatively small outlet nue, a pressure-operated fuel burner disposed axially of said tubular chamber and adjacent said flame intake end for projecting a central burning core of fuel longitudinally through said chamber and against said opposite end, the wall of said chamber being formed with a flue gas outlet near its flame intake end, whereby when flame is forced to travel centrally through the combustion chamber toward said closed end flue gases travel in a reverse direction substantially through the combustion chamber in the form of a ring or envelope surrounding the traveling flame and finally pass through said flue gas outlet, said flue gas outlet comprising a pair of apertures and tubular heat exchangers communicating with said chamber through said apertures and extending parallel to and spaced from said chamber in a direction toward said closed end whereby said gases pass into said exchangers and through the exchangers in the same direction as said flame.

'7. In combination a housing, a burner outside of one Wall thereof, a name passage extending axially from the burner inwardly through such Wall and terminating short of the opposite wall of the housing, a second flame passage generally parallel with the first, joined thereto inside the housing, adjacent the burner and extending out- Wardly through the opposite wall of the housing, a header outside said opposite wall into which such latter passage discharges, and a conduit extending outwardly through the Wall of the housing joining the axial passage and the header, the cross-sectional area of the conduit being substantially less than the crosssectional area of the axial passage.

8. In combination a housing, a burner outside of one wall thereof, a flame passage extending axially from the burner inwardly through such Wall and terminating short of the opposite wall of the housing, a second flame passage generally parallel with the first, joined thereto inside the housing, adjacent the burner and extending outwardly through the opposite Wall of the housing, a header outside said opposite wall into which such latter passage discharges, and a conduit extending outwardly through the Wall of the housing joining the axial passage and the header, the cross-sectional area of the conduit being sub stantally less than the cross-sectional area. of the axial passage, the cross-sectional area of the second passage being substantially less than the cross-sectional area of the axial passage.

Number 8 Name Date Pitman May 31, 1927 Taylor Nov. 5, 1929 Sauvage Deo. 3, 1929 Lundi; et al. May'30, 1933 Mikeska Dec. 4, 1934 Ross Apr. 2, 1935 Macchi Nov. 26, 1935 Wilson Dec. 15, 1936 ODowd Dec. 5, 1939 Kittel Jan. 2, 1940 Brown July 29, 1941 Mueller Nov. 18, 1941 Elze July 21, 1942 Kumler Oct. 5, 1943 

